Method of making containers



Oct. 7, 1930. F. A. PRAHL METHOD OF MAKING CONTAINERS Filed July 6', 126 'QCZ i Illlln lllllIIlI Ill Patented Oct. 7, 1930 UNITED STATESPATENT OFFICE FREDERICK A. PRAHL, OF CHICAGO, ILLINOIS, ASSIGNOR TOCONTINENTAL CAN COM- PANY, INC., OF NEW YORK, N. Y., A CORPORATION OFNEW YORK METHOD OF MAKING CONTAINERS Application filed July 6, 1926.Serial No. 120,716.

The invention relates to new and useful improvements in the method ofmaking a metal container.

An object of the invention is to provide a container made from metalplates coated in the sheet with the non-oxidized metal prior to thecutting of the sheets and the forming of the body of the containerwherein the side edges of the body portion are lapped and securedtogether, and the edge of the inner lapped portion of the side seam iscoated with the non-oxidized metal, the same as the side faces of thesheet.

A further object of the invention is to provide a method of making acontainer of the above type wherein the sheet is so trimmed and coatedprior to the cutting of the same into blanks, that the edge of thelapped portion of the side seam of the body portion of the container iscoated with a non-oxidizing metal.

These and other objects will in part be ob vious and will in part behereinafter more fully described.

In the drawings which show by way of il-' lustration one embodiment ofthe invention Figure 1 is a vertical sectional view through a portion ofa container embodying 0 my lmprovements;

Fig. 2 is a transverse sectional view through the container;

Fig. 3 is a detail of a portion of the side seam Viewed from the insideof the container;

Fig. 4 is a plan view of a black sheet with the edges trimmedpreparatory to the coating of the sheet;

Fig. 5 is a view of the sheet after it is coated and the manner ofcutting the sheet into tainers from tin plate by cutting the plates intoblanks and then rolling the blanks and lapping the edge portions thereofto form the side seam, these lapped portions being permanently securedtogether by soldering. The blanks are formed by cutting the metal afterthe black sheets are coated with tin, and as a result, the cuttingthrough of the sheet exposes the iron or black plate forming the bodyportion of the sheet and on which the coating is placed. When the edgeportions are lapped to form the body as above noted, this forms acontainer wherein there is an exposed edge of the iron plate on theinner surface of the container. The present invention is directed to acontainer wherein this edge which has usually been exposed is coveredwith the tin so that the entire inner surface of the container after itis'formed is coated with tin. The invention is also directed to a methodof forming such a container wherein the coating of the edge which hasheretofore been exposed is accomplished during the coating of the sidefaces of the black plate with the tin. In carrying out the invention,the black sheet which is provided for coating with tin, is trimmed sothat the width of the plate is twice the width of a blank used in makingthe body of the container. After the sheet has been thus prepared, it ispassed through the molten tin, and

the entire sheet, including the edges, coated with tin. The sheet isthen split down through the middle and cut transversely so as to formthe blanks. By this method of first trimming the sheet and then coatingit with tin, the body blank can be formed wherein one edge at least atthe side of the blank is coated with tin. The blank is then rolled intoa body in such a way that this edge which is coated is on the inside ofthe container.

Referring more in detail to the drawings, my improved container consistsof a body portion 1 having the edge portions 2 and 3 overlapped andsecured together permanently, preferably by soldering. This body portionis formed of sheet metal and preferably of a black steel sheet coatedwith tin. The sheet is so coated that the edge 4 of the edge portion 2is coated with tin. The article Wlll 3Q by the cutting of the blank ison the outside possiblybe better understood by a description of themethod of making. The black steel sheet indicated at in Fig. 4c of thedrawing is trimmed along the lines a, a and b, b so as to term a sheetwherein the width of the sheet a is twice the width of the blank used inthe forming of the body portion of I the container. The sheet is thenpassed was formed.

on the inside of the container.

through a molten bath of tin and coated with tin. The side faces, andalso the edges of the entire sheet are coated with the tin. The plate 5is then out along the line 0, c, which is midway between the side edgesa, a and h, h of the plate. After the sheet is cut along the line 0, ,c,it is then out along transverse lines as indicated in Fig. 5, so as toform blanks for the body which are indicated at 6.. The body blank isshown in plan in Fig. 6. The edge 7 of this body blank was one of themarginal edges of the main plate, and therefore, it is coated with tin.The other edges of the body blank are out after the sheet is coated, andof course, the steel will be exposed along these edges. The body blankis then rolled into the body of the container in such a way that theedge 7 of the blank is onthe inside of the container as indicated at 4in Figures 1 and 2 of the drawin The edge 7', is on the outside of thecontamer, and therefore, any iron or steel which is exposed of thecontainer. The edges 8, 8 of the blank 6 are at the top and bottom ofthe container, and when the ends .9 are attached to the formed body,these edges 8, .8 are rolled into the double seam, and therefore, theexposed iron or steel is concealed both from the inside and the outsideof the container.

it will be seen from'the above that I have provided a method of forminga container wherein the sheets may be coated with the tin in the usualway, and then cut into proper size blanks, after which each blank ispassed through a bod maker, and the body completed by the apping oftheside portions and the securing of the side portions together. Allthat is necessary is to properly stack the blanks after they are cutfrom the sheet and feed the blanks'after they are stacked into the bodymaker in such a way that the coated edge will be on the inside of thelapped seam. After'the container is made, the steel sheetforming thebody portion of the metalsheet is entirely covered on the inside of thecontainer, and this prevents any possible rusting or oxidization of theiron or steel The container, in effect, is free from oxidization, as it7 would be if the metal plate was coated with tin' after thebody'portion of'the container .While I have referred to the use of tin.for coating the steel plates, it will be understood that any othernon-oxidizing metal may be used. While I have also described arness thesteel sheet as being coated by passing the same through a molten bath oftin, it will be understood that it may be coated in any other way, theonly essential feature being that the sheet shall be trimmed, and themethod of coating shall be of such a character as to not only coat theside faces of the sheet, but also the edges of the sheet. It will beunderstood, therefore, that i do not use the term coating in a limitedsense, but any method of depositing the tin on the sheet describedabove, and the container, when completed, will be precisely the same asthat described above, except that the side faces and the edge of thesheet steel plate will be coated with the lacquer.

It is well understood that the edges of the cold rolled sheet whenprepared for coating in the usual manner, are distorted and carry acertain amount of scale which prevents the metal coating from adheringto the same. By my improved method, however, wherein the sheet of steelafter it is cold rolled and just before it is coated with tin, istrimmed, a clean edge is assured, to which a non-oxidizing metal willstick and cover the edge as well as the side faces of the sheet.

While I have described a round container,

it will also be understood that the container may be otherwise shaped,without departing from the spirit of the invention as set forth in theappended claimi- Having thus described the invention, what I claim asnew and desire to secure by Let-.

container so that at least one side edge of the blank is coated with thenon-oxidized metal shaping said blank into the body portion of thecontainer with the side portions thereof lapped so that the coated edgeis on the inside of the container, and permanently securing said lappedside edge portions.

In testimony whereof I afiix my signature.

FREDERICK A. PRAHL.

